JPH029579A - Shot-peening device and method - Google Patents

Abstract

PURPOSE: To provide constantly uniform shot peening treatment to products by providing a sensor to detect a shot amount in a specified zone in a shot blowing passage, and output an amount signal based on this shot close to a discharge port of a shot peening gun. CONSTITUTION: When a shot 20 is supplied to a shot peening gun 14 to jet the shot 20 from a nozzle 34 of the gun, a shot amount in a specified zone in a shot blowing passage 16 is detected by a sensor 44 provided close to the nozzle 34 of the gun 14, and an amount signal (m) is generated based on the detected amount. In addition, reaction force of the gun 14 by blow of the shot 20 is detected by another sensor 38, and a force signal F is generated based on the detected force. By a computation means based on the force signal F and the amount signal (m), parameters selected among a group of mass flows R and average shot particulate sizes (v) are computed.

Description

BACKGROUND OF THE INVENTION This invention relates to shot peening and, more particularly, to shot peening such as calculating shot mass flow rate and shot average velocity.

The use of shot peening is relatively well known. In particular, a stream of shots (ie, particles) is directed at a surface at high velocity. The shot is directed at the workpiece surface, causing plastic deformation of the workpiece surface, usually a metal surface. Shot peening is often used to increase fatigue strength, but
This method may also be used for other purposes.

Over the years, various shot peening devices and methods have been developed.

Shot peening equipment typically has (or can easily be equipped with) a mass flow controller. This controller is used to control the flow of shots to the shot pinning gun. A common type of quality R:L flow control device used for shot made of magnetic materials is pulse driven to allow a metered shot to pass through the shot peening gun. It has an electromagnet. This common type of mass flow controller is
Internal feedback is used to stabilize the mass flow rate (ie, the amount of shot metered in a given period of time). A controller can be used to set the mass flow rate to the desired value. A display device is often used to display the flow rate.

Conventional shot peening equipment, either as part of the mass flow controller or as a separate component, had various shot flow meters that indicated the flow rate of the shot. The Schott flowmeter may be a magnetic density meter, an example of which is the Model 260 Schott flowmeter manufactured by Electronics Inc. of Indiana.

The sensor of a magnetic densitometer, typically represented by the 260 model, is a coil of wire wrapped around a tube through which the shot passes vertically. Basically, this device measures the amount of shot that is under the coil at a given time by sensing the inductance of the coil. In the amount of time it takes for the shot particles to pass the length of the coil, any shot in the coil is replaced by new shot.

Therefore, L is the length of the coil (inches), T is the time the shot passes through the coil (seconds), ■ is the velocity of the shot (inches/second), m is the amount of shot inside the coil (bond), If and R is the R12 flow rate of the shot (17 seconds), then the mass flow rate of the shot through the coil is R-m/T (17 seconds) (1), and v-L/T (inches/second) (2) Therefore R-mv/L (Bonn 17 seconds) (3) Mass flow O
In order to solve for R, the coil of a 260 type magnetic density meter is
Install it in the shot supply piping at the bottom of the shot flow control valve in the vertical direction. The average velocity V of a shot falling freely within the coil from a trajectory shot is a known constant.

, the fort meter determines rn as A11l, and since the values ■ and L are known constants in this format, the signal processing part of the flowmeter calculates equation (3) and generates a signal representing the mass flow rate R. do.

The most important process parameters in a shot peening operation are the individual shot CD velocity and the shot mass flow rate. The flow rate determines how quickly the entire surface is struck. For a given exposure time,
If the flow rate is too low, certain areas of the surface will remain untreated after exposure is complete. On the other hand, if the mass flow rate is too high, the cold working of the surface may be too intense, leading to damage to the surface and making it susceptible to excessive fatigue. The velocity of the shot determines the amount of energy or cold work applied with each impact;
This governs the surface contour and the depth of the compressed layer. The energy of a shot particle is half the product of the particle's mass and the square of the particle's velocity. From this dependence of kinetic energy on particle velocity, it is clear that shot particle velocity is an important factor in determining shot peening quality.

Although certain measurement methods have been used in conjunction with shot peening methods, most conventional methods
The peening method was inadequate to produce a quality indication conveniently and inexpensively. The general lack of an easy and inexpensive way to measure shot peening quality has limited confidence that consistent shot peening results will be achieved.

Additionally, some shot peening equipment has been unable to detect malfunctions such as clogged nozzles or air leaks and take corrective action. As a result of this inability to detect malfunctions, workpieces may pass through the process without being shot peened.

Another problem is that some prior methods required measuring mass flow adjacent to the shot hopper and at a significant distance from the gun. The problem with this approach is that fluctuations in shot flow characteristics due to flow instabilities, leaks, knot formation, shot hose blockage, or other factors between the sensor and the gun can cause
11Pj, there is always the possibility of inaccuracies occurring.

Depending on variations in shot flow characteristics, this measurement error can be significant.

OBJECTS AND SUMMARY OF THE INVENTION The primary object of this invention is to provide a new and improved shot peening apparatus and method.

A particular objective of this invention is to quantify shot peening parameters so that consistent results are easily obtained.

Another object of the invention is to provide highly accurate Al1 determination for shot pinning by using a sensor in the shot peening gun itself to eliminate inaccuracies that would otherwise occur. It is.

Another object of the invention is to detect malfunctions that may interfere with proper shot peening operation.

Another object of the invention is to provide an arrangement that can be easily used with existing shot peening guns.

The above objects of the invention, as well as other objects as will become apparent from the following description, are achieved by a shot peening apparatus having a shot peening gun having a nozzle with an outlet.

A sensor is adjacent the outlet and the shot sprayer senses the amount of shot in the area within the passageway. The sensor has a coil adjacent the outlet and a sensing circuit operable to sense the amount of ferromagnetic shot within the coil by sensing the inductance of the coil. A sensing circuit generates a volume signal representative of the amount of shot within the coil. The shot peening gun is installed at the base and
and a force sensor that senses reaction forces due to gun operation. A force sensor is used with a device that generates a signal representative of the reaction force caused by the shot being ejected from the gun. Relate the reaction force to an unknown shot velocity and an unknown quality flow rate. Since the volume signal representing the amount of shot inside the coil is related to the known length of the sensor coil, the unknown shot velocity, and the unknown quality flow, the sensor coil and force sensor can be combined together. For example, two equations are obtained for the two unknowns: average shot velocity and mass flow rate. Therefore, two unknowns are solved by a series of calculations. That is, the average shot velocity and/or mass flow rate can be determined using a sensor located at the shot peening gun, and this measurement is sensitive to variations in shot flow characteristics between the sensor and the gun. Because it is not subjected to any interference, very accurate results can be obtained.

The method of the invention includes providing shot to a shot peening gun, activating the gun to expel the shot from a nozzle of the gun, sensing the amount of shot within a volume adjacent a nozzle exit of the gun, and sensing the reaction force of the force and generating a force signal. The method further includes calculating a velocity signal representative of the average velocity of the shot from the nozzle exit and/or calculating a mass flow signal representative of the flow rate of the shot applied to the face of the workpiece being shot peened. including. Preferably, both the average velocity signal and the mass flow rate signal are calculated and the mass flow rate and average velocity are displayed.

A test circuit may be provided to trigger an alarm or detect a malfunction within the device when it detects a malfunction, as indicated by the sensed reaction force, the amount of shot in the sensing coil, the mass flow rate, and/or the average shot velocity. Turn off various parts.

The above Jfl and other features of the present invention will be better understood from the detailed description of the drawings below.

The same reference symbols are used throughout the drawings to refer to similar parts.

detailed explanation FIG. 1 shows the shot peening operation of the present invention.

In particular, workpiece 10 has a surface 12 that receives shot peening from shot peening gun 14 . Shot peening gun 14 establishes passageway 16 by displacing shot fed to gun 14 through shot supply piping 18 that carries shot 20 from hopper 22 . The shot is supplied to supply piping 18 via flow controller 24 .

The flow controller may be a conventional type of flow controller that uses an electromagnet to dispense a metered amount of metal shot, although other types of flow controllers may also be used.

Flow controller 24 can also provide a mass flow signal in a known manner via control lines (not shown in the figures). However, the present invention determines mass flow rate in another advantageous manner, which will be explained in more detail below.

This approach avoids flow inaccuracies such as those caused by blockages between mass flow controller 24 and gun 14.

Shot supplied to gun 14 from supply line 18 is entrained by pressurized air from air nozzle 26 at the end of air supply conduit 28 . An air supply conduit 28 supplies pressurized air from a source 30 of pressurized air via a line regulator 32 . This leveler is used in a known manner to level and adjust the air pressure supplied to the gun 14. In particular, the pressure of the air supplied to nozzle 26 is such that nozzle 34 and gun 1
Helps determine the speed of the shot that will be driven from 4. Gun 14 is attached to bracket 36.

The components shown in FIG. 1 described above are standard components.

The shot peening gun 14 is a gravity type shot peening gun.
This is a peening gun. Although the invention will work with other types of shot peening guns, such as suction lift guns or pressure pot guns, the following discussion will be directed to the use of the invention in a gravity shot peening gun.

Gun 14 has a bracket 36 attached to a force sensor 38. A force sensor 38 is located between the gun 14 and a base 40 that supports the gun 14 . Force sensor 38
is preferably a directional strain gauge that detects force parallel to the direction in which the shot is ejected from gun 14. In other words, the force sensor 38 has a substantially 3 g relationship to the +, i vertical force of gravity acting on the gun 14. However, force sensor 38 detects the reaction force of gun 14 as it discharges the shot into passageway 16. A force sensor 38 is connected to a signal processing circuit 42, which provides a force signal F. Although other force sensors may be used, the force sensor 38 may be manually available as a Revault load cell type 3397 on the market, and the signal processing circuitry may be connected to a corresponding transducer device 7537.
It may be.

These two components are often seen as a package. The signal processing circuit 42 is basically a force sensor 38
The output from the converter is converted into a form corresponding to the number of force bonds so that the output can be displayed and/or recorded. The use of such force sensors in shot peening equipment is described in pending US Patent Application Serial No. 138.004, filed December 28, 1987.

A sensor 44 is mounted adjacent to the outlet of the nozzle 34 and is fixed in position by a ring-shaped clamp 46. The detailed structure of sensor 44 will be described below, but it should be noted that sensor 44 has a coil (not specifically shown in FIG. 1) that is electrically connected to sensing circuitry 48.

A sensor 44, including a sensing circuit 48, acts as a known magnetic densitometer. Specifically, sensing circuit 43 internally generates a signal based on the inductance of a coil within sensor 44 . Since the inductance of the coil within the sensor 44 is related to each ferromagnetic shot within the coil, the sensing circuit 48 produces an output m representative of the mass of the ferromagnetic shot within the coil. The fill senses the shot in a portion of the passageway 16 extending from the outlet of the supply line 18 to the face 12. The details of the calculations used to generate the mass signal from the coil in a magnetic densitometer are relatively well known and need not be explained in detail. The use of this sensor located at the nozzle outlet is described in previously cited pending US patent application Ser. No. 188,826.

This invention, together with a portion of the design of this U.S. patent application,
It will be appreciated that the present invention may incorporate other features of these other two applications, as they also include portions of the design of similar serial number 138,004.

Next, referring to FIG. 2, the structure of the sensor 44 will be explained in detail. FIG. 2 is a cross-sectional view of sensor 44 at the tip of nozzle 34 of gun 14. FIG. The sensor 44 can be clamped to the end of the nozzle by a ring-shaped clamp 46 with a tightening screw 50. The ring-shaped clamp 46 may be generally of the same type as hose clamps commonly used to secure garden hoses to inner connectors. For this purpose, we have a ring 52 and tighten it by tightening the screw 50. The sensor 44 is cylindrical and has the same outer diameter as the tip of the nozzle 34, so that the hose clamp 46 can be matched to the outer diameter of the nozzle and the outer diameter of the sensor 44. Sensor 44 includes a coil 54 mounted on a non-ferromagnetic core 56. A steel magnetic flux concentrator 58 extends on three sides of the cross section of the coil 54. coil 5
4. The core 56 and concentrator 58 both extend cylindrically around the outlet at the tip of the nozzle 34. The preferred material for the core 56 is from a relatively harsh environment corresponding to shot;
The coil 54 is made of polyethylene to protect it. In addition to excluding foreign objects, the ring-shaped steel flux concentrator 58 concentrates the magnetic field set up by the coil 54 to an area inside the coil 54 .

The configuration of sensor 44 of FIG. 2 allows the apparatus of the present invention to be used with previously existing shot peening guns 14 (only a portion of which is shown in FIG. 2). The sensor 44 is
The hose clamp 46 can be easily clamped onto the end of a conventional shot peening gun. Alternatively, the sensor 44 can be mounted to the tip of the nozzle end of the gun 14 using a bracket (not shown) or a series of brackets (not shown). When using the configuration shown in Figure 2, as shown in Figure 1,
A standard shot peening gun 14 (see FIG. 1) can be used by also installing a force sensor 38.

FIG. 3 shows another configuration in which a sensor 144 is incorporated into the shot peening gun 114 to sense shot spray in an area within the passageway 116.

It will be appreciated that the parts of the embodiment of FIG. 3 have the same last two digit reference numerals as corresponding parts, if any, as compared to the configuration or embodiment of FIG. The sensor 144 is
It is integrated into gun 114 adjacent the tip of nozzle 134 . In particular, the nozzle 134 has a cylindrical recess 1
60 in which a coil 154 is seated. Further, a side surface 162 of the cylindrical steel magnetic flux concentrator 158 extends downwardly toward the cylindrical recess 1δO. Sensor 14'4 operates similarly to sensor 44 and in conjunction with sensing circuitry (not shown). Polyethylene is very resistant to abrasion, so it is used in nozzle 1 of gun 114.
Can be used for 34 materials.

Before describing how sensors 38 and 44 are used to determine mass flow rate R and average shot particle velocity V,
Let me explain some of the mathematics involved.

Newton's second law of motion states that force is equal to two changes in motion. Motion 2 is the quality mm multiplied by the velocity 2, which can be expressed as follows.

d dv
dmF --(mv) fem+v
dt dt
dtTypically, this equation results in F-ma. Here, a is acceleration, which is the first term on the right side of equation (4) (,
This corresponds to this. A force is applied to an object of constant mass.

However, for a shot pinning gun in steady state, the first term is zero since the velocity does not change. Therefore, quality] is equal to velocity multiplied by the difference in mass. Applying equation (4) to the shot stream can be seen as somewhat analogous to pulling a lobe out of a seedling by pulling it at a constant speed. The first term in the equation is zero because the time derivative of velocity is zero.

However, the second term of equation (4) holds true in the sense that the mass of the rope changes as it is pulled out from the box. In a somewhat similar way, changes in the movement of the shot flow are
Its mass flow rate multiplied by its velocity. That is, the velocity V of the shot flow is as follows.

v = F B / R (5) where R represents the mass flow rate corresponding to dm/dt, V is the average velocity of the shot stream, and Fs is the force of the shot stream.

Equations (5) and (3) explained above define the two unknowns as F
There are two equations. Magnetic density of type 260 +i l
Note that in the discussion of ', equation (3) can be solved since the velocity of the shot is a known constant corresponding to a free-falling shot.

Equation (3) can be applied to sensor 44 (FIG. 1), where the ferromagnetic shot '11m inside the coil and the length of the coil are known. The unknown mass flow rate R and the unknown average shot velocity V can be determined using equation (3) in conjunction with equation (5).

Solving equation (3) for V gives v −RL / m (6)
If we set the right side of equation (6) to be equal to the right side of equation (5), then F s / R = v = RL / m
(7). If we solve this equation (7) for R, then R
-(FB m/L) '' (8) Substituting the above result obtained for R into equation (5) gives v-(FS L/m) 112 (9) From the above, the average shot speed V and mass flow 12
It turns out that R can be determined from the reaction force, the mass of the shot inside the coil at a particular time, and the known length of the coil (the exponent 1/2 indicates the square root of the equation)
.

Equations (8) and (9) are executed by the configuration shown in FIG. The output of signal processing circuit 42 is F, which is a signal corresponding to the reaction force as the gun discharges the shot and air. This signal can be fed to a force display device 200 to allow the operator to observe the total reaction force of the gun. This force is equal in magnitude and in direction anti-λ·l to the force of the shot and air displaced from the gun. This force signal is then applied to the positive power of differential amplifier 202 . The negative input of differential amplifier 202 is
It is connected to the force signal via switch 204 and sample-and-hold circuit 206. Differential amplifier 202 allows for the most accurate determination of the gun reaction force due to the shot being ejected. In particular, when air is being expelled from the gun, and before the operator turns on flow controller 24 (only shown in FIG. 1), all reaction force sensed by sensor 38 is due to air. Therefore, during that time, if the operator presses the temporary switch 204,
The sample and hold circuit 206 can store a signal Fa corresponding to the reaction force due to air alone. The reaction force signal Fa due to this air is transmitted to the differential amplifier 202.
is supplied to the negative terminal of Therefore, when the operator turns on the flow controller 24 and shot peening begins, the previously stored voltage level from the sample and hold circuit 206 is subtracted from the total force signal F and the reaction due to the shot peening is subtracted from the total force signal F. A signal or voltage level Fs corresponding to the force is taken out.

The output Fs of the differential amplifier 202 is supplied to a multiplier 208. This multiplier multiplies the signal m corresponding to the mass inside the coil of coil sensor 44. The output of multiplier 208 is provided to divider 5210, which divides the product of multiplier 208 by a signal representing the known length of the coil. As shown, the signal may simply be a constant voltage derived from a voltage divider comprised of resistor 212 and variable resistor 214. The output of divider 210 is provided to a square root circuit 216, which takes the square root of the output of divider 210. The result is a mass flow signal R, which can be displayed on flow display 218.

Multiplier 220, divider 222, and square root circuit or function generator 224 can also be used to determine a signal V corresponding to the average particle velocity, which can be displayed on velocity display 226.

FIG. 5 shows an alarm circuit for use in the apparatus of FIG. The circuit of FIG. 5 is a portion of the same circuit as FIG. 4, but is shown separately for clarity. Various signals from the circuit of FIG. 4 are provided to the circuit of FIG. 5, which will now be described.

The signal F corresponding to the output of the signal processing circuit 42 in FIG.
5 is provided to comparator 228 of FIG. It should be appreciated that the reaction force F is the overall reaction force or recoil of the gun 14 due to the ejection of the shot as well as the release of the gas. If this reaction force is too small, it is due to the shot supply piping 18
This indicates a malfunction such as a blockage or leak in the air conduit or supply line 28. Comparator 228 therefore acts as a comparison means to ensure that force signal F has a predetermined minimum value. In the apparatus of FIG. 5, a comparator 46 compares the force signal F with the signal FMIN or AMIN.

In particular, the alternating voltages are provided by controlled switches 230, 232, such as FETs.

The gate of switch 230 is provided with a shot on signal that is high or positive when shots are being expelled from the gun. When not displacing shots, the signal is zero. The shot-on signal is supplied to the flow controller 24 in FIG.
can be simply supplied using the voltage supplied to turn on the . Although not shown separately in Figure 1,
The flow controller 24, of course, has a power circuit to power it when dispensing or passing a shot. The same known signal that powers the controller 24 may be used as the shot-on signal, or the shot-on signal may be converted by converting the power to the controller 24 to another voltage level or another type of signal. may be supplied.

When the shot on signal is low, corresponding to no shot being delivered to the gun, switch 232 is turned on by inverter 234, but switch 2
30 is off or open.

Therefore, voltage AMIN is provided to comparator 228 and compared with force signal F. Voltage AMIN corresponds to the minimum reaction force that should be sensed at any time when line conditioner 32 is supplying air to the shot peening gun, even when not expelling shot. When flow controller 24 is turned on to begin delivering shot to the gun, a shot on signal is provided, switch 232 is turned off, and switch 230 is turned on. Comparator 228 then compares the total force signal F to a voltage FMIN that corresponds to the minimum reaction force that should be sensed when the gun is discharging a shot.

As can be readily seen, the voltage levels FMIN and AMIN corresponding to the minimum reaction force with shot flow and the minimum reaction force without shot flow, respectively, are similar to resistors 212 and 214 in FIG. It can be set by a voltage divider with a variable resistance so that it can be adjusted by the user.

When the force signal F is less than a selected minimum value (depending on whether a shot is being fired), comparator 228 has a positive output when the total force signal F is less than the minimum value. The positive output of comparator 228 is provided to OR gate 236, the output of which is the stop progress signal. A stop progress signal is provided to alarm 2iii 238. Additionally, this signal can be provided to controlled power switch 240 to shut off power to the device. The power switch 240 is a relay,
A switching transistor or other controlled switch turns off the shot peening operation. Power switch 240 may cut off power to flow controller 24 or otherwise stop it from delivering shots to the gun. Furthermore,
Power switch 240 may cut off power to plumbing regulator 30 or otherwise stop air from passing to the gun. The line conditioner 32 may include a suitable control 242 that sets the air pressure supplied to the gun. When the alarm 238 sounds,
The operator is notified that the shot peening operation has been stopped.

If the overall reaction force is less than the selected minimum value,
In addition to stopping the shot peening operation and sounding the alarm, the circuit of Figure 5 includes a series of test circuits that are used to verify that other parameters of the equipment are within acceptable limits. Guarantee.

As shown, a test circuit 244 for testing the value of ■ includes a comparator 246 and a comparator 248. If the speed signal V is lower than the minimum allowable speed vmin or higher than the maximum allowable speed vmax, appropriate comparators 246 and 248
outputs a positive signal, which passes through OR gate 250. If the output of ORG 250 is positive, it indicates that test circuit 244 has determined that speed signal 2 is outside the boundaries of an acceptable range.

Test circuits 252, 254 and 256 are test circuit 244
It is possible to compare the values of the mass flow rate signal R1 shot reaction force signal Fs and the coil mass signal m to ensure that each signal is within an acceptable range. If those signals are outside the acceptable range,
It represents some malfunction. For example, if the value of m becomes too small, it indicates that not enough shots are reaching the gun, and there may be a blockage between the shot hopper 22 (only shown in Figure 1) and the gun 4. Show that something is true. The allowable minimum and maximum values for the four fiflv, R, F5 and m are determined by resistors 212, 2 in FIG.
It can be set by an adjustable voltage divider similar to 14. All test circuits 244.252, 254, 25
6 may have the same configuration, but instead a simpler form that only guarantees that some value did not fall below a minimum value, or a simpler form that only guarantees that a certain value did not exceed a maximum value. You can make it into any shape. Various test circuits 244.
The outputs of 252, 254, and 256 are provided to OR gate 258. If the output of gate 258 is true, it indicates that at least one of the four parameters tested is outside its correct range.

One of the four parameters tested by the test circuit
Until the shot peening operation reaches a steady state, for example, the output of gate 258 may be outside the desired range, so the output of gate 258 is
60 and the other power is connected to a delay device 262 which receives the shot on signal. Thus, an indication of a malfunction due to one or more of the four signals being outside the tolerable range will continue after the predetermined delay time established by delay device 262. It does not pass through the gate 260 unless the voltage falls outside of the range to interrupt the shot peening operation. The output of gate 260 is provided to OR gate 236.

The operation of the device is the comparison section 111. Referring to FIG. 1, when the line conditioner 32 is energized, a flow of air is emitted from the gun 14. The flow control 24 remains closed and no shots are ejected. The operator can then momentarily press button 204 to sample and hold the reaction force due to the ejected air, as described with respect to FIG.

Comparison 2W228 when only air is released (Figure 5)
ensures that the total reaction force is not so low as to indicate an air leak or other malfunction.

After sampling the reaction force signal, open switch 204;
Power is supplied to the flow controller 24 so that the shot is delivered to the gun 14.
so that it starts to flow. Power is supplied from a standard power circuit for the flow controller and a shot-on signal indicating the initiation of a shot peening operation is supplied to the alarm circuit of FIG.

A differential amplifier 202 provides a force signal F, to which coil sensor 44 (or 144 in FIG. 3) is used to
A mass signal rn is provided. These two signals are combined with the signal representing the length of the coil to perform the necessary calculations to determine the mass flow rate R and the average shot particle velocity V.

After a short delay from turn-on of flow control 79F24 (this delay being set by delay device 262), various test circuits 244, 252, 254, 256 determine whether the associated signal is within an acceptable range. . If not within range, gate 260 outputs a positive pulse, which passes through gate 236 and is sent to alarm 2 as a stop signal.
38 and also to power control switch 240 .

The illustrated device calculates R and V based on Fs, but one can either use F instead and accept the lower accuracy (e.g. assuming an air reaction force from that pressure). The air reaction force may be compensated for in some other way, such as by taking into account the pressure of the air supplied to the gun. More generally speaking, Fx
Let F be the force signal F or any signal derived therefrom, the calculation may be F,X.

Although various specific embodiments and configurations have been described, it should be understood that these are examples only. Various modifications will occur to those skilled in the art. For example, by various circuit devices,
Although circuit components have been described that perform calculations on analog signals, digital components can alternatively be used to generate multiplications, divisions, and square roots. Additionally, a microprocessor may be used to perform the operations described herein.

Accordingly, reference should be made to the claims for determining the full scope of the invention.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a shot peening apparatus according to the present invention and a side sectional view of a shot peening gun having a sensor according to a first embodiment, and FIG. 2 is an enlarged sectional view of a portion of the sensor according to a first embodiment. , FIG. 3 is a side sectional view of a portion of the sensor of the second embodiment, FIG. 4 is a circuit diagram of an electrical device of the invention including some of the components shown in FIG. 1, and FIG. 5 is a diagram of the invention. 1 is a circuit diagram of an alarm device that can be used for Explanation of main symbols 14 Yacht peening gun 16: Shot spraying passage 34: Nozzle 38: Force sensor 42: Signal processing circuit 44: Sensor

Claims (1)

[Claims] 1. A shot peening gun having a mounting base, a shot peening gun supported by the mounting base and having a nozzle having an outlet; Based force signal F
a force sensor operable to generate a force sensor adjacent said outlet for sensing the volume of shot within an area within the shot delivery path and for generating a volume signal m based on the sensed shot; a sensor operable to receive said signals F and m and operable to calculate a shot peening parameter selected from the group consisting of a mass flow rate R and an average shot particle velocity v; A shot peening device having operable calculation means. 2. The shot peening apparatus of claim 1, wherein said calculation means is operable to calculate both R and v and includes display means for displaying mass flow rate and average shot particle velocity. 3. The calculation means calculates the following formula R=(F_sm/L)^1^/^2 v= where F_s is the portion of F due to the reaction force of shot displacement and L is the dimension of the area. (F_sL/m) can act to calculate R and v by (F_sL/m)
Shot peening equipment as described. 4. The shot peening apparatus of claim 1, wherein the sensor includes a coil adjacent the outlet and a sensing circuit that senses the amount of shot within the coil by sensing the inductance of the coil. 5. The shot peening apparatus of claim 4, wherein the coil is wrapped around the nozzle. 6. The shot peening apparatus of claim 4, wherein said coil is wrapped around a core of non-ferromagnetic material for said nozzle. 7. A shot peening apparatus as claimed in claim 4, wherein the calculation means is operable to calculate both R and v and includes display means for displaying mass flow rate and average shot particle velocity. 8. The calculation means calculates R according to the following formula R=(F_xm/L)^1^/^2, where F_x is the force signal F or a signal derived therefrom and L is a signal representing the length of the coil. 5. A shot peening device according to claim 4, which is capable of acting on a shot peening device. 9. The calculation means calculates v according to the following formula v=(F_xL/m)^1^/^2, where F_x is the force signal F or a signal derived therefrom and L is a signal representing the length of the coil. 5. A shot peening device according to claim 4, which is operable. 10. The shot peening apparatus of claim 4, further comprising an alarm and test circuit operable to detect a malfunction condition and to activate an alarm when a malfunction condition is detected. 11. The shot peening apparatus of claim 1, further comprising an alarm and test circuit operable to detect a malfunction condition and to activate an alarm when a malfunction condition is detected. 12. A power switch and a test circuit operable to detect a malfunction condition and to turn off the power switch and stop shot peening when a malfunction condition is detected. The shot peening device according to item 1. 13. supplying shot to a shot peening gun, operating the gun to expel the shot from the nozzle of the gun, and displacing the shot in an area proximate the nozzle exit of the gun and within the shot delivery path; sensing the volume, generating a volume signal m based on the sensed volume, sensing the reaction force of the gun on ejecting the shot, generating a force signal F based on the sensed force, and generating a mass flow rate R
and a mean shot particle size v using a force signal F and a volume signal m. 14. The method of claim 13, including the step of displaying the calculated parameters. 15. The method of claim 13, wherein both R and v are calculated. 16. The method of claim 15, including the step of: displaying mass flow rate and average shot particle size. 17. Let F_s be the portion of F that is due to the reaction force of shot displacement, and L be the dimension of the area, as follows: R=(F_sm/L)^1^/^2 v=(F_sL/m)^1 14. The method of claim 13, comprising calculating R and v according to ^/^2. 14. Sensing 18, 12 is performed by a coil adjacent to the outlet and a sensing circuit for sensing the shot in the coil by sensing the inductance of the coil and generating a quantity signal m. the method of. 19. Claim 1 comprising the step of testing for the presence of a malfunction condition and activating an alarm when a malfunction condition is detected.
The method described in 3. 20. The method of claim 13, including the steps of: testing for a malfunction condition; and ceasing operation of the shot peening gun upon detecting a malfunction condition.